Map Class of Service (CoS) Settings to Differentiated Services Code Point (DSCP) Values on RV120W and RV220W

Objective

Class of Service (CoS) is a 3 bit field within an Ethernet frame header when we use 802.1q which supports virtual LANs on an Ethernet network. This field specifies a priority value which is between 0 and 63 inclusive which can be used in the Quality of Service (QoS) to differentiate traffic. The Differentiated Services Code Point (DSCP) is a 6-bit field in the IP header for the classification of packets. Differentiated Services is a technique which is used to classify and manage network traffic and it helps to provide QoS for modern Internet networks. It can provide services to all kinds of networks.

CoS works on Layer2 and DSCP on Layer3. CoS values will exist in 802.1q tags (a 12bit VLAN identifier) and a DSCP value will exist in IP header at all times. The mapping is useful to know where the appropriate marks are to their respective queue. Mapping is also used to evaluate packet for schedules and assign packets to one of the queue purposes.

This document explains how to map the CoS settings to DSCP values on RV120W and RV220W.

Note: Before the user can map the CoS settings to DSCP values, the user must ensure that the CoS to Queue Option is enabled. For further details of how to enable the CoS to Queue option please refer to the article Configuration of Class of Service (CoS) 802.1p to Queue Mapping on 200/300 Series Managed Switches.

Applicable Devices

• RV120W 
• RV220W

Software Version

• v1.0.4.17

Map CoS Settings to DSCP Values

Step 1. Log in to the web configuration utility and choose QoS > CoS Settings > CoS to DSCP. The CoS to DSCP page opens:

Step 2. Check Enable in the CoS to DSCP field.

Step 3. Enter the CoS value you want to map to the DSCP in each 802.1 Priority field. This area has various priority levels. The value ranges from 0 to 63. The default value is 0.

Note: Priority 0 has the highest priority and Priority 63 the lowest.

Step 4. Click Save to save the settings.

Note: To revert settings to default settings, click the Restore Default button.